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The transition between convective and radiative stellar regions is still not fully understood. The sharp variations in sound speed located in these transition regions give rise to a signature in specific seismic indicators, opening the…

Solar and Stellar Astrophysics · Physics 2023-05-10 M. Deal , M. -J. Goupil , M. S. Cunha , M. J. P. F. G. Monteiro , Y. Lebreton , S. Christophe , F. Pereira , R. Samadi , A. V. Oreshina , G. Buldgen

Perturbations of rotating relativistic stars can be classified by their behavior under parity. For axial perturbations (r-modes), initial data with negative canonical energy is found with angular dependence $e^{im\phi}$ for all values of…

General Relativity and Quantum Cosmology · Physics 2009-10-30 John L. Friedman , Sharon M. Morsink

Using our non-local time-dependent theory of convection, the linear non-adiabatic oscillations of 10 evolutionary model series with masses of 1--3M$_\odot$ are calculated. The results show that there is a red giant instability strip in the…

Astrophysics · Physics 2008-11-26 D. R. Xiong , L. Deng

Opacity enhancements for stellar interior conditions have been explored to explain observed pulsation frequencies and to extend the pulsation instability region for B-type main-sequence variable stars. For these stars, the pulsations are…

Solar and Stellar Astrophysics · Physics 2018-06-19 Joyce A. Guzik , Christopher J. Fontes , Chris Fryer

We use perturbation theory and the relativistic Cowling approximation to numerically compute characteristic oscillation modes of rapidly rotating relativistic stars which consist of a perfect fluid obeying a polytropic equation of state. We…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Stratos Boutloukos , Hans-Peter Nollert

We study prospects for seismic sounding the layer of a partial mixing above the convective core in main-sequence stars with masses in the 1.2 -- 1.9 solar mass range. There is an initial tendency to an increase of convective core mass in…

Astrophysics · Physics 2007-05-23 B. L. Popielski , W. A. Dziembowski

Pulsational properties of 1.8 M$_{\odot}$ stellar models covering the latest stages of contraction toward the main sequence up to early hydrogen burning phases are investigated by means of linear nonadiabatic analyses. Results confirm that…

Astrophysics · Physics 2009-11-06 Marian Suran , MarieJo Goupil , Annie Baglin , Yveline Lebreton , Claude Catala

The frequency ratios $r_{01}$ and $r_{10}$ of KIC 11081729 decrease firstly and then increase with the increase in frequency. For different spectroscopic constraints, all models with overshooting parameter $\delta_{\mathrm{ov}}$ less than…

Solar and Stellar Astrophysics · Physics 2016-04-15 Wuming Yang

The fundamental ($f$-) mode gravitational waves from cold low-mass neutron stars are systematically studied with various equations of state (EOSs) characterized by the nuclear saturation parameters, especially focusing on the phenomena of…

High Energy Astrophysical Phenomena · Physics 2020-10-07 Hajime Sotani

Tens of thousands of red giant stars in the Kepler data exhibit solar-like oscillations. Their oscillations enable us to study the internal physics from core to surface, such as differential rotation. However, envelope rotation rates have…

Solar and Stellar Astrophysics · Physics 2024-08-21 Gang Li , Sebastien Deheuvels , Jerome Ballot

The evolution of rotating stars with zero-age main sequence (ZAMS) masses in the range 8 to 25 M_sun is followed through all stages of stable evolution. The initial angular momentum is chosen such that the star's equatorial rotational…

Astrophysics · Physics 2008-11-26 A. Heger , N. Langer , S. E. Woosley

Understanding the physical properties of star-forming cores as mass reservoirs for protostars, and the impact of turbulence, is crucial in star formation studies. We implemented passive tracer particles in clump-scale numerical simulations…

Astrophysics of Galaxies · Physics 2025-01-08 Shingo Nozaki , Hajime Fukushima , Kazuki Tokuda , Masahiro N. Machida

Excitation of radial oscillations in population I (X=0.7, Z=0.02) red supergiants is investigated using the solution of the equations of radiation hydrodynamics and turbulent convection. The core helium burning stars with masses 8M_odot <=…

Solar and Stellar Astrophysics · Physics 2015-06-03 Yuri A. Fadeyev

Oscillation modes of a mixed character are able to probe the inner region of evolved low-mass stars and offer access to a range of information, in particular, the mean core rotation. Ensemble asteroseismology observations are then able to…

Solar and Stellar Astrophysics · Physics 2024-01-17 B. Mosser , G. Dreau , C. Pincon , S. Deheuvels , K. Belkacem , Y. Lebreton , M-J. Goupil , E. Michel

We calculate light curves produced by $r$-modes with small azimuthal wavenumbers, $m$, propagating in the surface fluid ocean of rotating neutron stars. We include relativistic effects due to rapid rotation, and propagate photons from the…

Astrophysics · Physics 2009-11-10 Umin Lee , Tod E. Strohmayer

The problem of the gravitational radiation damping of neutron star fundamental ($f$) mode oscillations has received considerable attention. Many studies have looked at the stability of such oscillations in rapidly rotating stars,…

General Relativity and Quantum Cosmology · Physics 2022-01-07 Garvin Yim , D. I. Jones

Solar-like oscillations have been observed by Kepler and CoRoT in many solar-type stars, thereby providing a way to probe the stars using asteroseismology. We provide the mode linewidths and mode heights of the oscillations of various stars…

Delta Scuti (delta Sct) stars are opacity-driven pulsators with masses of 1.5-2.5M$_{\odot}$, their pulsations resulting from the varying ionization of helium. In less massive stars such as the Sun, convection transports mass and energy…

Using linear non-adabatic pulsation analysis, we explore the radial-mode (p-mode) stability of stars across a wide range of mass (0.2 <= M <= 50 Msun), composition (0 <= X <= 0.7, Z=0.001, 0.02), effective temperature (3 000 <= T_eff <= 40…

Solar and Stellar Astrophysics · Physics 2016-03-09 C. S. Jeffery , H. Saio

Rapidly oscillating Ap stars are unique objects in the potential they offer to study the interplay between a number of important physical phenomena, in particular, pulsations, magnetic fields, diffusion, and convection. Nevertheless, the…

Solar and Stellar Astrophysics · Physics 2015-06-17 M. S. Cunha , D. Alentiev , I. M. Brandão , K. Perraut
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